1. Field of the Invention
The present invention relates to a spindle motor.
2. Description of the Related Art
Generally, an optical disk driver reads or records data from or in an optical disk. The optical disk driver includes a spindle motor that rotates the optical disk at a high speed, and an optical pickup module that stores data in a track of the optical disk rotating at a high speed and reads the data stored in the track of the optical disk.
The spindle motor includes a turntable coupled to a rotating shaft to support an optical disk and a centering unit that aligns the rotating center of the optical disk with a rotating shaft.
The turntable is press-fitted over the rotating shaft to rotate along with the rotating shaft, whereas the centering unit moves up and down in the axial direction of the rotating shaft. That is, a gap is formed between the centering unit and the rotating shaft.
The turntable is first coupled to the rotating shaft of the spindle motor. After the turntable is coupled to the rotating shaft, the centering unit is coupled to the rotating shaft.
As the turntable and the centering unit are coupled together to the rotating shaft of a limited length, a coupling area (or contact area) of the turntable with the rotating shaft is reduced, thus undesirably reducing a coupling strength of the turntable with the rotating shaft, and causing a rotational slip between the turntable and the rotating shaft.
Further, if thickness of the turntable increases so as to increase the coupling area of the rotating shall with the turntable, the overall size of the spindle motor undesirably increases.